Microtome blade holder



Feb. 18, 1941. v s MacDONALD 2,232,008

MICROTOME BLADE HOLDER Filed Jan. 20, 1939 INVENIOR ATTORNEY Patented Feb 18, 1941 I UNITED STATES PATENT OFFICE MICROTOME BLADE HOLDER Georges. MacDonald, Buffalo, N. Y., assignor to Spencer Lens Company, Buffalo, N. Y., a corporation of New'York Application January 20, 19.39 Serial No. 251,990 4 Claims. (01-. 88-40) This invention relates to a microtome blade at each stroke of. said work holder, to feed the holder, and, more particularly, to. a blade. holder same forwardly whatever distance may be desired, which can be used in present day microtomes. and so that the paraffin block or other work piece I3 is able to employ a safety razor blade as the cutbeing operated upon by the microtome, succesting means in place of the usual and difiicult-tosively moves outwardly and then downwardly 5 resharpen ordinary microtome knife. against the cutting edge M of the razor blade The principal object of the invention is to. proand thereby cuts on successive laminations from vide a blade holder of this character which will said work piece t3.

grip the razor blade very firmly with a. minimum The work holder I2 is oriented in the usual: and

of manual effort and irrespective of the thickness. well known manner relatively to the main reciprow or shape of the razor blade. Another object of eating head 16 of the microtome by means of a the invention. is to provide a microtome blade number of oblique orienting screws l'l or otherholder whose main body member may be conwise. The parafii-n block or other work piece I3 struoted of soft and easily machined material but is suitably cla p between e j and f9 15 is provided with a suitable wear block to withstand of the work' holder [2 by means of the clamping 15 the heavy twisting pressures of the clam-ping screw 20. screws which are to be found in most present day The present invention relates solely to the means microtomes. A still further object of the invenfor cutting the work piece It and consists'primation is to provide suitable spacing feet on the blade y of a ma dy member 2 Which is Suitably 2Q holder so that when said holder is not beingv used held in the carriage 22 of the microtomeby a in the microtome, but is lying upon a supporting or" clamping screws 23 or otherwise. As illussurface, the cutting edge of the razor blade is trated in the drawing thi main b y ember 2| elevated above the supporting surface and is is clamped at its opposite ends in the microtome, thereby prevented from injury; Numerous other but it is to be understood that the present invenobjects of the invention and practical solutions tionis not confined to any such specific mounting 25 thereof are described in the following specificaarrangementbecause for certain work with slidtionand illustrated in the attached drawing ing microtomes it has been found desirable to wherein: secure one end only of the main body member 2| Fig. 1 is-a diminutive-front elevation of. onetypeto the microtome'. Said main body 2| comprises of microtome'showing the improved bladeholder a base: plate 24 and an overhanging portion 25 30 in Working D fi therei'fli which is secured to said base plate 24 by means of Fig; 2 is an end elevation of the: blade holder counter sunk: machine screws 26 or otherwise. with-atypical form of razor blade clamped therein. Said overhanging portion 25 is provided with an Fig. 3 is a front elevation thereof with certain upwardly and forwardly inclined wedgingsurface parts b k away, 2'! which. terminates at its outer end in a thrust 35 Fig. 3a is a front elevation of one of the wear nose 28a The latter issomewhat rounded so as plates prior to its being assembled in the knife to prevent excessive local stresses at its extreme holder. outer end; The portion of the base plate 24 Figs. 4, 5 and 6 are vertical transverse sections Which faces is pp s a d thrust nose 28 40 through the blade holder taken on the comey be nv n n lydenominatedaclamping face 40 spondingly numberedljnes of Fig. 3 29 and it is against this clamping face that the Fig. 7 is a fragmentary longitudinal section. rear face of the razor blade I5 is adapted to bear. through one end of the blade holder taken on line Adapted to b r a ainst the front face of said 1 1, Fi 3., razor blade [5 is a clamping head 3% which is sub- Fig. 8. is a horizontal longitudinal section or the nti' lly tr angular in cross-section, its base 32 45 blade holder taken on line 8-8" of Figs. 2 and 3. constituting a clamping face which bears against Similar characters of reference indicate like the front face of the razor blade while its apex parts throughout the several figures of the 33 is adapted to make contact with the thrust drawing. nose 28 of the overhanging portion 2'! of the main 1 In Fig. l is shown a typical form of: what is body member 2|. 50 known as a rotary microtome. In. this form of Secured centrally to said clamping head 3!, as

microtome' manual power is applied to the handle best shown in Fig. 4, is a pull rod fi l. The conll of the wheel I I and this power, through the nection between said pull rod 34 and the clamping instrumentality of well known mechanism, isv used head 3t may be effected in any desired manner 55. to reciprocate vertically the Work holder 12 and, as, for instance, by threading the upper end of said pull rod 34 into said clamping head 3| and looking it in place by a suitable lock pin 35 which is driven into a suitable hole drilled perpendicularly into the base 32 of the clamping head 3| and into the upper end of said pull rod 34. The central part or shank of said pull rod 34 is received within a U-shaped clearance opening 36, this clearance opening being economically formed by suitably milling the overhanging portion 25 of the main body member 2| prior to its being assembled to the base plate 24 of said main body member. The lower end of the pull rod 34 is threaded to receive a clamping nut 31 which, when rotated in a clockwise direction, as viewed from the bottom of Fig. 4, bears upwardly against the lower flat face of the main body member 2| and pulls the clamping head 3| downwardly. This action causes the razor blade I 5 to be firmly clamped between the clamping face 29 of the base plate 24 and the clamping face 32 of the clamping head 3|. It will be noticed that as the clamping nut 3! draws the clamping head downwardly, the clamping face 32 of the clamping head remains at all times substantially parallel to the clamping face 29 of the base plate 24, thereby permitting razor blades of varying thicknesses to be securely clamped in the blade holder. It should also be noticed that the only part of the overhanging portion 21 of the main body member 2| which is in contact with the clamping head 3| is the nose '28 so that said clamping head 3| is enabled to slightly rock to compensate for any irregularities in thickness of the razor blade l5. This enables a large area of the razor blade to be clamped and permits said razor blade to be firmly clamped between the two clamping surfaces 29 and 32 under all circumstances.

In the ordinary type of microtome the clamping screws 23 exert a very vicious twisting force upon the main body of the blade holder. Heretofore this has resulted in the blade holder becoming very rough and unsightly after a relatively short period of use. In the present invention such a condition is prevented by providing a pair of hardened steel wear blocks 38 whose function is to take the brunt of the twisting thrust caused by the clamping screws 23. These wear blocks permit the main body member 2| of the blade holder to be constructed of soft and relatively easily formed material with the twisting thrust of said clamping screws taken care of by said wear blocks which are constructed of a hard material and are of such shape as to be easily machined. These wear blocks 38 are arranged in the main bodymember 2| of the blade holder as follows: Formed in the front vertical face of the base plate 24 of said main body member is a reverse flared socket 40 which is formed by passing a flared end mill longitudinally inwardly from the outer edges 4| and 42 of the base plate 24. As a consequence of this machining operation, the socket 40 has two straight parallel reverse-flared side walls while its inner end also has a reverse flare and is of semi-circular shape. To make a wear block 38 of the same shape as this socket 40 would be prohibitively expensive and in the present invention each of said wear blocks 38 is constructed with its longitudinal side edges bevelled so as to snugly fit between the side walls of said socket 40 while its inner end is not bevelled but is machined so as to have a semi-circular end which is square cut as best shown in Fig. 3a. This construction results in a cavity between the inner portion of v each socket 4L and the inner end of its companion wear block 38. To fill up this cavity, a suitable amount of liquid solder or other plastic material 43 is placed in the socket 411 and then the companion wear block 38 driven into place. This permits the base plate 24 to be electroplated by the plating 44 with the wear blocks 38 in position, without enabling any of the plating solution or the washing solution to work its Way into any interstices between the wear blocks 38 and the sockets 40. It is obvious, that, instead of using a plastic material 43, a material such "as ordinary solder may be used inasmuch as the same is plastic when heated. It is also obvious that this plastic may be eliminated entirely if the base plate 24 and the wear plates 38 are plated individually and said wear plates then driven into place.

When the microtome knife holder is not in use it is desirable to provide means to prevent the razor blade l5 from coming into contact with the table or other surface upon which it is being supported when not being used in the microtome. This result is effected in the present invention by providing two spacing feet 45 which are preferably of the round headed shape shown, with their shanks of the self-threading type so that when they are driven into suitably located holes 46 they are rigidly and permanently retained'therein. The construction line shown in Fig. 2 represents the table or other supporting surface 41 upon which the blade holder is supported when not being used in the microtome and illustrates how the razor blade I5 is prevented from coming into contact with said supporting surface 41.

It is to be understood that the present invention is not to be restricted to the scope of the present disclosure, but includes all variations which come within the essence of the invention and the scope of the appended claims. For instance, the blade holder may be used not only to hold ordinary safety razor blades, but to hold any flat replaceable cutting blade such as, for instance, the relatively thick, steel blades of isosceles trapezoidal shape used for cutting wall board. Furthermore, the invention is not to be confined to use in rotary microtomes but includes the use in other types of microtomes such as those of the sliding type, parallel link type, table type, etc. Furthermore, the shape of the main body member 2| is not to be restricted to the form shown in the drawing but includes a main body member having a base plate 24 provided with a clamping face 29 but otherwise of any shape whatsoever and connected at either one or both of its ends to a microtome in any manner whatsoever.

I claim:

1. A microtome blade holder for use with a blade having a normally flexible body tapering into a knife-like cutting edge, said holder having a supporting portion with a clamping surface adapted to engage a side surface of the blade throughout substantially the major portion of the area of said side surface with substantially only the cutting edge of the blade exposed and having a portion disposed on the opposite side of said blade having an outwardly extending surface terminating in a thrust-like nose adjacent its free edge, a wedge-like clamp head having a substantially triangular cross-section with the base of said triangle having a clamping surface shaped to engage the major portion of the opposite side surface of the blade and the apex of said triangle adapted to make contact with the thrust nose of the portion having the outwardly extending surface, said extending surface, inwardly of said thrust nose, being spaced from the adjacent surface of the clamp head whereby said clamp head is enabled to slightly rock on said nose to compensate for any irregularities in thickness of the blade, and means for imparting a substantially straight line movement to said head for urging the apex of the triangular like shape thereof into engagement with the thrust nose and the clamp surface on the base thereof into binding and clamping relation with the blade with the said head being so dimensioned that when in binding relation with said blade a portion of said blade adjacent its cutting edge is exposed.

2. A microtome blade holder for use with a blade having a normally flexible body tapering into a knife-like cutting edge, said holder having a supporting portion with a clamping surface adapted to engage a side surface of the blade throughout substantially the major portion of the area of said side surface with substantially only the cutting edge of the blade exposed and having an outer surface tapering to a relatively thin edge adjacent the cutting edge of the blade and a portion dmposed on the opposite side of said blade having an outwardly tapering surface terminating in a thrust-like nose adjacent its free edge, a wedge-like clamp head having a substantially triangular cross-section with the base of said triangle having a clamping surface shaped to engage the major portion of the opposite side surface of the blade and the apex of said triangle adapted to make contact with the thrust nose of the portion having the outwardly tapering surface, said tapering surface, inwardly of said thrust nose, being spaced from the adjacent surface of the clamp head whereby said clamp head is enabled to slightly rock on said nose to compensate for any irregularities in thickness of the blade, and means for imparting a substantially straight line movement to said head for urging the apex of the triangular like shape thereof into engagement with the thrust nose and the clamp surface on the base thereof into binding and clamping relation with the blade with the said head being so shaped and dimensioned that when in binding relation with said blade a portion of said blade adjacent its cutting edge is exposed and an outer surface portion of said head tapers to a relatively thin edge adjacent said cutting edge.

3. A microtome comprising means for supporting an object from which specimens are to be cut, a carriage having clamp means, a blade holder secured to said carriage by said clamp means and having a normally flexible blade with a knifelike cutting edge therein, said blade holder having a supporting portion with a clamping surface engaging a side surface of the blade throughout substantially the major portion of the area of said side surface with substantially only the cutting edge of the blade exposed and having a portion disposed on the opposite side of said blade having an outwardly extending surface terminating in a thrust-like nose adjacent its free edge, a wedgelike clamp head having a substantially triangular cross-section with the base of said triangle havinga clamping surface engaging the major portion of the opposite side surface of the blade and the apex of said triangle contacting the thrustlike nose of the portion having the outwardly extending surface, said extending surface inwardly ofsaid thrust nose being spaced from the adjacent surface of the clamp head whereby said clamp head is enabled to slightly rock on said nose to compensate for any irregularities in thickness of the blade and means for imparting a substantially straight line movement to said head substantially in the direction of the plane of a side surface of the blade for urging the apex of the triangular-like shape thereof into engagement with the thrust nose and the clamping surface of the base thereof into binding and clamping relation with the blade with the said head being so dimensioned that when in binding relation with said blade a portion of said blade adjacent said cutting edge is exposed.

4. A microtome comprising means for supporting an object from which specimens are to be cut, a carriage having clamp means, a blade holder secured to said carriage by saidclamp means and having a normally flexible blade with a knife-like cutting edge therein and having hardened bearing plates for receiving the clamping pressure of said clamp means, said blade holder having a supporting portion with a clamping surface engaging a side surface. of the blade throughout substantially the major portion of the area of said side surface with substantially only the cutting edge of the blade exposed and having an outer surface tapering to a relatively thin edge adjacent the cutting edge of the blade and a portion disposed on the opposite side of said blade having an outwardly tapering surface terminating in a thrustlike nose adjacent its free edge, a wedge-like clamp head having a substantially triangular cross-section with the base of said triangle having a clamping surface engaging the major portion of the opposite side surface of the blade and the apex of said triangle contacting the thrust nose of the portion having the outwardly tapering surface, said tapering surface inwardly of said thrust nose being spaced from the adjacent surface of the clamp head whereby said clamp head is enabled to slightly rock on said nose to compensate for any irregularities in thickness of the blade and means for imparting a substantially straight line movement to said head substantially in the direction of the plane of a side surface of the blade for urging the apex of the triangularlike shape thereof into engagement with the thrust nose and the clamping surface of the base thereof into binding and clamping relation with the blade with the said head being so shaped and dimensioned that when in binding relation with said blade a portion of said blade adjacent said cutting edge is exposed and an outer surface portion of said head tapers to a relatively thin edge adjacent said cutting edge.

GEORGE S. MACDONALD. 

